public class BTree {

    static class TreeNode{
        public char val;
        public TreeNode left;
        public TreeNode right;

        public TreeNode(char val){
            this.val=val;
        }
    }

    public TreeNode creatTree(){
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');

        A.left=B;
        A.right=C;
        B.left=D;
        B.right=E;
        C.left=F;
        C.right=G;
        E.right=H;

        return A;
    }
    public void preOrder(TreeNode root){
        if(root==null) return;
        System.out.println(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }
    public void inOrder(TreeNode root){
        if(root==null) return;
        inOrder(root.left);
        System.out.println(root.val+" ");
        inOrder(root.right);

    }
    public void postOrder(TreeNode root){
        if(root==null) return;
        postOrder(root.left);
        postOrder(root.right);
        System.out.println(root.val+" ");

    }
    public static int nodesize =0;

    public int size(TreeNode root){
        if (root==null){
            return 0;
        }
        nodesize++;
        size(root.left);
        size(root.right);
        return nodesize;
    }




}
